This application relates to a rotor shaft for use in a generator, wherein the rotor shaft is configured to more efficiently utilize space.
Generators are known and typically include main windings that rotate with a rotor shaft. The rotor shaft is selectively driven to in turn drive the main windings adjacent to a stator, and the rotation of the windings relative to the stator generates electricity.
Modern generators have a number of additional accessories. As an example, an exciter rotor and a permanent magnet rotor are also attached to the rotor shaft. In addition, a rectifier assembly may communicate with the exciter rotor. The rectifier assembly has been mounted within a hollow rotor shaft, however, the exciter rotor has typically been at the end of the shaft. A wire can communicate to the rectifier assembly from the exciter by merely extending around the end of the shaft. The requirement of mounting the exciter rotor at this location provides an undesirable design constraint.
In addition, there have been compromises with regard to the size of the shaft. Typically, a clutch member includes splines that selectively transmit rotation to the rotor shaft. The clutch member must be able to slide such that it can be engaged or disengaged from a drive input. The splines have typically been provided at one end of the rotor shaft. Having the spline connection at either a remote end or an adjacent end of the rotor shaft results in a clutch member that is either too long or too short for many design applications.
Furthermore, generators are typically designed such that they will always operate at a frequency that is below a first natural frequency of the overall assembly. To achieve this goal, it is desirable to increase the rotor outer diameter, and to decrease the distance between supporting bearings for the rotor. However, the requirement of including several operational components has made achieving these goals challenging.